These drive devices are not new per se. Pumps utilizing drive devices of the general type to which the present invention relate generally comprise a pump rotor mounted in a pump chamber and a pump cover surrounding the rotor having a neck defining a housing bore and a shaft rotatably journaled in the housing bore. The drive pulley is supported by an outer bearing on the lateral surface of the neck and the shaft is supported in an inner bearing in the housing bore of the neck. The bearings are typically designed to absorb radial and axial load. In accordance with a well known prior type, the inner ring of the radial and axial load supporting outer bearing is seated on a cylindrical lateral surface section at the neck of the pump cover. The end surface of the inner ring, which faces the pump chamber, is supported on a ring-shaped peripheral should surface of the neck. This arrangement is shown in West German Pat. No. 3,716,098,2.
The shoulder surface is usually continuous about the periphery and in order to form this shoulder, the pump cover must either be designed with thick walls or its neck must be designed in the shape of a "z" in longitudinal cross section at the area of the shoulder surface. It has been found that fabrication of the pump cover with a drive device of the type described can be extremely expensive by reason of the fact that a large amount of material must be machined away to form the shoulder. It is likewise cumbersome and expensive to recess the shoulder in the form of a "z" at the point of the transition from the section of larger diameter to the section of smaller diameter.